I can comment on lighting and fans, but not the hydro side, as I'm new to that part myself (I've been growing under lights in soil). I'll be assuming, from your lighting comments, that this is for indoors.

Fans: Ostensibly this will help you build stronger stems. I found little benefit to it, but it sure dried out my medium quickly. I stopped using the fan I bought.

Are fluorescents "good enough": Yes. The only type of light that's not "good enough" is incandescent.

What to look for in lighting: It depends on what you want your grow to look like. Fluorescent, MH, and HPS are all about the same plant-growth energy efficiency. Higher-frequency spectrums are better for leafing, while lower frequency is better for flowering and fruiting. With fluorescents, since they're not very intense, you need a ton of them, inches from your plants. MH and HPS let you have a more sparse lighting setup, as they're more concentrated. LED are more efficient than all three of those. The downsides to LED are higher capital cost and poor compatibility with some kinds of plants. The capital cost issue is actually a red herring, as you'll spend more on power to run the less efficient systems than you will on fixtures. The latter is a real issue; don't bother trying to grow, say, lettuce under red-blue LEDs (although other plants, like basil and peppers, will love you for it). LED lights also have the advantage that you don't need to cool the space that they're in; you should generally have a ventillation system set up for rooms operating a significant number of fluorescents, MHs, or HPSs.

Darkness: No, plants do not need total dark at night. The research I've seen and my own personal experience show that you get much better growth by leaving lights on 24/7.

For lettuce, Shop lights will work, Just keep the lights close to the canopy, no more than 2" away, closer will not hurt.

Contrary to the other post, plants do better with a dark period. They can survive and even thrive when they are young with 24/7 light but if you look at nature, it gets dark for a while each day. Yet plants thrive. Why waste money on lighting when it isn't needed?

Just thought I would mention that in Alaska during summer months they get light 24/7. For a couple of hours during the middle of the night it's more like twilight because the sun is just below the horizon, but it never actually sets and becomes dark. That's why they call it the Land of the Midnight Sun. They also grow some of the largest fruits and vegetables in the world, and it cant just be the soil.

I've seen research that suggests plants do better with a period of rest. Why do all the potheads grow on an 16/8 schedule? to maximize yield. That's not to say you can't grow with 24/7 lighting, just that at some point the plant get exhausted , so to speak.
I CAN go 48 or even 72 hours without any sleep (yes I have done it) but the results are nowhere near as fruitful as getting a few hours of sleep in there.

One person on Gardenweb did a controlled experiment with peppers last year. The growth difference was staggering; the 24-hour peppers towered over the shorter photoperiod peppers. I've seen other comparisons elsewhere that were the same. This matches my personal experience, and the experience of most people on this site who've tried it.

Every so often you'll see a study that says that "over a certain point, there's no benefit or even a small detriment" -- but if you look into them, you'll find that they're often using a *lot* of light, and are likely hitting the rate limit on how fast sugars can move out of the leaves. But you pretty much have to be as bright or brighter than the sun for that.

I saw the experiment in question and yes, for the eight week period they did much better under 24/7. But I've read numerous studies that show that after 8-10 weeks, the plants show more degradation, necrosis and less growth with constant light. Over a longer period (~18 weeks) the 24/7 plants were nearly dead.

That doesn't even make sense. Most food crops, including peppers, are C3 plants. They don't have a separate CO2-fixation and photosynthesis stage; it's a single stage. So they can only "work" when there's light out. Contrary to the name, the "dark" or "light-independent" reactions (Calvin cycle) only takes place when light is out, just like the light-dependent reactions.

These aren't humans; they don't "sleep". They're constantly growing, day and night, but their available energy for growth is limited by the light that they get.

Now, there are hormonal things caused by day length in some plants -- namely, some types of plants won't flower unless the night is long enough. But that obviously only affects plants that you care about them flowering, and only a small fraction of those are short day plants (strawberries being the most common example found in hydroponics; cannabis is partially affected as well, which is why many growers drop the photoperiod at flowering stage)

I agree with karenrei, just wanted to say that it was my understanding that some varieties (day neural varieties) of strawberry's were not really subject to flowering depending on hours of light. And yes people feel fatigued if they don't get enough sleep, but it's the human (or animal) brain that gets fatigued, and plants don't have brains.

I was lurking here while adding some pictures to my database and read this thread about "brains". Of course plants have "brains". It just doesnt have the animal part to drag them around. We just got the luck of the draw. Animals just started out developing symbiotic relationships rather than IÂm going to eat you. Take away your body for a few minutes. That leaves just your brain. Look at how itÂs set up. You have a left side and a right. With plants you have the roots and the leaves. Both are strictly the same. You have a stem connecting the two. Just like your brain. Your brain forms million of connection to help you learn. One side takes care of the day to day task, math, logic. The other takes care of art and imagination. I know you wonÂt argue the math and logic part but art and imagination. Of course plant have to have those things to attract YOU and the rest of the animal community. Plants put huge efforts into both. DoesnÂt an attractive person attract you and makes you want to move closer? A flower does the same thing. Those millions of connections? Roots in the soil touching millions of things just like the brains in our heads. Memories, someone posted about plants only taking and leaving the rest. Sorry plants never forget. Like you a plant can recall just like you. If a root runs into say copper, iron, or some element it needs but not right now that root tip may die off but the when the plant needs it recalls where that was in the soil and reconnects. Adhesion, cohesion. Remember those two their not just for water transport. As for getting tired thatÂs because of the animal carrying us. Without that who knows how much, how little or even if weÂd need sleep.

georgeiii
By your definition, my foot has brains (even sock), It has connections, so therefore brains. Is there anything on the planet that does not have connections, even bacteria comes in contact with other bacteria. So I guess all bacteria has brains. Talk to a scientist. Only the plants in your garden have brains because you have not been able to comprehend reality yet. To be honest, I'm even wondering if you do at this point.

Ha, that article says exactly what I was saying. Remember how I wrote:

Every so often you'll see a study that says that "over a certain point, there's no benefit or even a small detriment" -- but if you look into them, you'll find that they're often using a *lot* of light, and are likely hitting the rate limit on how fast sugars can move out of the leaves. But you pretty much have to be as bright or brighter than the sun for that.

Foliar accumulation of starch is a well-known indicator that you've surpassed the plant's ability to transport sugars from the leaves to the rest of the plant (it accumulates there instead of moving elsewhere to be stored or used in growth). It means that you're giving them energy faster than they can make use of it. Plants have a limit to how fast they can move photosynthesis products around.

In lab experiments, the growers spare no expense on lighting. Home growers, however, usually have too little light.

It's essentially impossible to hit the transport limit unless you surpass the energy being provided by the sun, since no plant will evolve to make more sugar than it can transport during days of full sun conditions where it is native to. The limit is often well past the amount it can get in full sun -- but let's just look at full sun. The sun imparts 1,000W/m^2 to the surface. Let's say that after night and illumination angles/shading, you only average 25% of that full exposure -- 200W/m^2 * 24 = 4800kWh of light energy. Most greenhouse lighting systems, excluding LED, get 10-20% efficiency at producing light (after adjusting for the difference between plants' ability to use different parts of the spectrum -- HPS is really bright to humans, for example, but not as bright to plants, who prefer light in the red and blue spectrum for photosynthesis). So you need about 32kWh of energy input per square meter per day to just match the sun -- 1.3kW continuous draw per square meter for a 24-hour photoperiod, or 2.7kW draw per square meter on a 12-hour photoperiod (250W/ft^2).

In the lab, scientists will readily do that, but who do you know that provides that much light at home? You'd max out a power strip after covering just six square feet!

The article was a study about supplemental lighting for greenhouse tomato and sweet pepper production; I presume it was done based on real-life greenhouse operations where the cost of lighting would be an important factor. It showed that 24-hr. lighting, again presuming normal light intensity seen in greenhouses, caused damage after about 8 weeks

Tomatoes and peppers need a little less than 3,000 Footcandles of light for 14 hours per day for high quality production. For MH lamps, that translates into ~100W/m^2 or 1.4kW hrs per day. They do not need 10,000 FC.

The facts speak for themselves: if you have starch accumulation in the leaves, you're producing energy faster than the plant can get rid of it. That's what that symptom means.

Tomatoes and peppers need...

More light = more photosynthesis, until you overload the plant's ability to transport sugar out of the leaves. More photosynthesis = faster growth.

I tell you what: find me a single case of anyone on this forum getting excess starch accumulation in the leaves (it's easy to test for -- boil in water, then in ethanol, then add iodine and look for color change). If you can, then *those* people should reduce their lighting (either through less hours or through less intensity). But I doubt you'll find anyone here who fits that situation.

I'll tell you what - stick to the facts and data, the info the study provided as well as other experiments done in this area and I'll be happy to reply. Otherwise - goodbye!

You invented the idea that the testers were running "a virtual sun directly overhead;" that was never mentioned in the study. It was a study related to supplemental lighting for greenhouse production of tomatoes and sweet peppers. Where on God's Green Earth do you formulate the idea these experimenters wanted to do a study that not a single grower would even think of embracing (creating a virtual sun).

Raising plants in a GH is based, at least in part, on moles per day delivered to a plant. But that is unrelated to the study that says that 24/7 light, after a while, causes problems

I do agree - no one is going to boil leaves in water and then ethanol then add iodine and report a color change. They will, unless they are stupid or hardheaded, rely on studies done by experts.

You invented the idea that the testers were running 'a virtual sun directly overhead;' that was never mentioned in the study.

I assume you'll support that claim by providing details about the lighting setup? I based my claim on what most studies I've read about plant growth under lights use very high powered lights (unless they're testing something about the lighting setup itself), and that home growers tend to give too little to their plants.

Raising plants in a GH is based, at least in part, on moles per day delivered to a plant.

Moles? Is that a joke? You don't measure light in moles, as moles say nothing about spectrum and have little applicability to photons. ;) Concerning plants, the best way to measure light is PAR or PUR, although the data for that is often not available. Next best is watts in the visible spectrum, and after that, your various lux/footcandle type measurements (which are actually weighted in the inverse of what photosynthesis wants). All of that over time, of course.

They will, unless they are stupid or hardheaded, rely on studies done by experts.

No; if they're stupid or hardheaded, they'll just pretend that all lighting setups are equivalent in terms of optimal photoperiod. And likewise, a stupid person would pretend that starch accumulation in leaves has nothing to do with the amount of light overwhelming transport out of the leaves.

>>Moles? Is that a joke? You don't measure light in moles, as moles say nothing about spectrum and have little applicability to photons. ;) It's apparent you know nothing about lighting as it relates to growing plants.

I see some crazy posts on Lettuce growing. Lettuce needs little of anything. Nutes almost nothing in the water grows nice lettuce. Use Grow one part solution, and be happy. I have tried florescent lighting and it does not cut the mustard in later plant growth stages, even in lettuce. Try some small 400 watt Metal Hylide lights later on once the plant starts to mautre.

Its pretty simple really. The more light the better the plant, and the harvest. But all plants need to rejuvinate.

So here is something to try for plants other than lettuce, basil, and other herbs. Get some 1KW lights, one per plant if you can afford the electical bill. Keep the lights on 16 hours, and then off for 8 hours. During the lights on timeframe. keep the nute solution very weak (about 25% of the suggested amount). During the lights off stage, increase the nutes (about 50% of the suggested amount).

(Yes folks people who sell nutrient solutions are out to make money. Plants only need a fraction of what they tell you they need)

Plants need more water in heat to survive, nutes almost do not matter when its hot and there is lots of light. However, over the no light period expect to see some scary amounts of nutes consumed.

What should we use for the starter seedlings? Are Sure To Grow Cubes a good platform for growing the seedlings? How long should we allow them to grow?

There are lots of ways to start seeds. But being you are newer to hydroponics, I would go with rapid rooters. You can use rockwool but you have to ph balance them before you. I would wait until the seedlings have their first true leaves before transplanting them to a DWC setup. HOWEVER I feel they are very delicate at that early age, so I usualy wait until they have 4-6 sets of true leaves.

Do we need to fan the plants?

You don't need a FAN, but it is benefical. Air circulation will help decrease the chances of mold. With only 6 plants, you won't have to worry about mold. But the potheads often times grow 100's of plants in a very small room. Also for my own plants they just seem to be happier. I have mine set to turn on 15 minutes evey 2 hours.

What should we use for a nutrient solution?

I've used 5 different brands of hydroponic nutrients. From the very expensive to the lower priced items as well. Normally I don't like to recommend brands, because they ALL work, and I like to let people make their own decisions. However when I first started I was overwhelmed with the number of different choices, that I wished someone would just say here try this.

MaxiGro 1-part Growing Formula (PROS: Its very cost effective and works just as well as the higher price liquid ones. My 2.2lbs bag made 670 gallons of nutrient solution. CONS: its a powder so you have to make sure you stir very well to mix it.)

Dyna-Gro Grow (PROS: PH balances very well with MY tap water. Price is good compared to other liquids. Mixes alot faster. CONS: Cost more per gallon then powder nutrients. Doesn't store as well.)

Dyna-Gro Foliage Pro (I haven't used this myself, but i've seen this recommended on alot of threads here on GW. But i've had a hard time finding this other then online. )

Are flourescent lights a good enough lighting source? What do we need to look for in the lights?

Good enough yes. If your going with the homedepot route. Get T8 shoplights without the bulbs. Then look for the Philips ALTO bulbs that are 5000k color temp and 2850lumens. The more lumens you get the better off you will be. Something to consider. A 175W Metal Halide setup will cost maybe $130-170. But your plants will grow more vigoursly.

***THe Key to growing with flourscent lights is to keep them as close to the plants as possible. I let my plants touch the bulb and then move it up 2 chain links.

Do the plants have to be in total dark at night?

The question asked was if it needed to be "totally" dark at night. The general answer is yes and no. It leads into two highly debated topics. Do plants need a dark period, and the second topic is if it has to be absolutely dark. Lets just say it doesn't need to be totally dark, but the darker the better. AS to the debate on wheather to have the lights on 24 hours a day or 16, I will let you experiment with it, and come to your own conclusions. My only recommendation is to have the lights on atleast the number of hours listed on the seed packet. If none is listed no less then 12hrs a day.

Please indicate anything else that we might have forgotten.

Key to hydroponics is PH! Keep the PH in check with your nutrient solution and you should be ok. The more air your roots have without drying them out, the better your plants will grow. There is a diminishing return on the amount of air supplied to the roots so dont be overly concerned.

DO NOT USE ALOT OF NUTRIENTS! There is an urge for ALL gardeners to put more Fertilizers or Nutrients to make the plants grow bigger and faster. LESS is definitely more in this case. Your plants can thrive on very little nutrients in a hydroponic setup. This is the one mistake I see the most often.

It's apparent you know nothing about lighting as it relates to growing plants.

Do you even know what a mole is?

If so, you'd know that it says *absolutely nothing* about energy, because it says *absolutely nothing* about spectrum.

PAR and PUR: Light adjusted for how effectively plants can use the spectrum
Watts: Light by raw energy content
Lux / Footcandles: Light adjusted for how effectively humans can see it (which is the inverse of how plants use it)
Moles: Particles (in this case, photons), with no accounting for energy content at all. And it's a unit that makes no sense for photons, since the point of a mole is define the atomic mass unit (which is approximately relative to the mass of the proton and neutron). Why you'd care about AMU when dealing with photons is beyond me.

The last time I checked. Tomatoes, Cucumbers, and Romain Lettuce were not photo-periodic. However I have been told that most plants transpire, (That is when they give off the excess water that they have utilized in the process of transporting nutrients), and that this "transpiration" process occurs when they are not manufacturing sugar through the action of sunlight (photosynthesis), which by coincidence would most likely be at night. Georgeiii has some good points. If you've ever forced a plant to bloom and ripen fruit more quickly by root pruning or shocking it with a super high phosphorus/low nitrogen nutrient thereby causing it to "think" that it is dying and that it must reproduce as quickly as possible, or better yet-if you've ever seen a Venus Flytrap devouring it's lunch, It's quite conceivable that plants do have "brains". However I think its probably just chemical reactions and electrical impulses. But then again isn't that exactly how our brains operate?
~Ken~

Only CAM plants close their stoma during the day. For all other plants (which is the vast majority of them), transpiration occurs at all times -- and since it's generally hotter during the day, it happens more during the day than at night. The CAM cycle is an adaptation for desert living.

The stoma have to be open to let CO2 in. So if the stoma are closed, no CO2 is getting in. C3 plants have no way of storing CO2 at all, and C4 plants have only temporary storage. So in C3 and C4 plants, you need transpiration at approximately the same time as photosynthesis. Only CAM plants store a day's worth of CO2 during the night.

"Although photosynthesis can happen in different ways in different species, some features are always the same. For example, the process always begins when energy from light is absorbed by proteins called photosynthetic reaction centers that contain chlorophylls."

Transpiration is a process similar to evaporation, it's how the plant sucks up the water (and nutrients) from the roots, and eventually evaporates out small pores in the leaves and stems.

"Mass flow of liquid water from the roots to the leaves is caused by the decrease in hydrostatic (water) pressure in the upper parts of the plants due to the diffusion of water out of stomata into the atmosphere."

"The rate of transpiration is directly related to the degree of stomatal opening, and to the evaporative demand of the atmosphere surrounding the leaf. The amount of water lost by a plant depends on its size, along with surrounding light intensity,[2] temperature, humidity, and wind speed (all of which influence evaporative demand)."

And no georgeiii does not have a good point. By that definition (and/or logic) a glass of vinegar has brains when you add a tablespoon of baking soda to it. That has a chemical reaction and therefore would be considers brains. So no, just having a chemical reaction and or electrical impulse is not the definition of having brains. No, the ability to think and reason involves the need for somthing called brain cells (also called gray matter to some people). The ability for a Venus Flytrap to close in on a fly is not a thought it had. It's a reaction to the fly triggering a spring like mechanism in the stem of the plant. The devouring of the fly is just the fly dissolving in a chemical given off by the plant. A plant will continue to grow roots, stems and leaves no mater what, and not just because a root was cut.

There is no brain cells involved, and there has never been a plant dissected that has ever been shown to have one single brain cell. Any distinction between so called plant brains and reality is just wishful thinking. As well as probably the result of some deep thought about the meaning of life, and trying to make sense of it. But is simply not based on any actual real science, or reality.

If you people keep up this talk of plants with brains you are likely to make some vegans suicidal. We really should start another thread on the differences of plants and animals and if plants have thoughts, feel pain, etc. I think such a discussion would be entertaining. Don't know how to get it going good, though.

Back in May, when arguing with my bud Lucas on here, I mentioned in a thread entitled "Ghost in the Machine (or the nutrient reservoir)?" that there was a lady that set me off over getting nasty with those that disagree. Guess what! It was Karenrei that I was referring to. Here's the thread from last June: LED Thread Just thought I'd share that for some perspective, here.

I remember that thread. It wasn't long after that thread karen quit playing with us.

And just to plug the plants vs animals angle, remember there are a lot of actions our bodies take that are done unconciously. We don't have to think to breath or think for our hearts to pump. Some of us don't have to think to open our mouths. that's often a good laugh.

To everyone mentioning that "the sun doesn't go down in Alaska during the summer months." OK - yes, you have a point, but it's also not direct light. Even living in Arizona it would take you a very long time to get sunburned standing out in the morning sun, compared to 12:00 P.M.

As an aside, I have a front flower garden, separated by a porch, with a dogwood on the left side providing shade between 12:00 and 3:00. Same plants on both sides with the exception of a habanero on the right. The peppers that get morning and afternoon sun, with shade in between can't be picked fast enough. The peppers on the right - the plants took longer to get up to speed, are not as fruitful, and I've lost one for some reason. Granted, there could be other reasons, and each plant is going to be different, but the peppers out front on the right are performing the same as the peppers out back, which also get full sun from 10:00 to 6:00.